A kind of out-there question... What is the range of possible problems, solutions, breakthroughs, insights, skills, etc. that come after you've earned your stripes as one of the best human engineers on Earth?
Personally, I like doing this where I can feel like a beginner again and resume the climb. Entrepreneurship will certainly do that, but it's certainly not for everybody.
Love this. Nothing better than deleting your 100% completion file and starting over in Pallet Town.
The default path is to continue working on engineering problems except with increasing levels of scope and complexity. If you decide to climb the management ladder, your work will diversify into other disciplines outside of engineering in order to make engineering more effective. Having a stronger alignment with Product and business functions will progressively increase as you get more senior (i.e. you'll be expected to play on the intersections of domains more).
Outside of what's on the corporate ladder. There's always another "game" you could start playing once you feel like you've actualized what you can do in the "engineering game".
Personally, I like doing this where I can feel like a beginner again and resume the climb. Entrepreneurship will certainly do that, but it's certainly not for everybody.
As someone who has been doing that, it feels really nice to start over, but I would always recommend to build up the side hustle and network while you have a job. Typically you want your side hustle to replace your main income while doing both jobs simultaneously 6-12 months before making the jump. I had to jump early as IBM's non-compete was on a whim they own your stuff. My wife's income can support us in perpetuity and we just have to carefully manage finances so I don't have to get a job. Not too bad, but go the former route if not comfortable with a super minimalistic lifestyle for a while. Typically takes 3 years or so hard work to build the business to a point it can become self-sufficient
If you've been a Senior Staff or Principal Engineer in Big Tech for more than 5+ years, you're likely financially free. (This is not always true due to lifestyle creep, but I know it to be true for many folks.)
What you do at that point depends on what you want to do:
A good example of someone I consider to be in this category is Philip Su.